Search

In engineering practice, layered rock masses often display obvious anisotropy while deforming and failing, and the failure mode directly impacts the engineering construction stability. In this study, the fracture failure load, fracture toughness, crack deflection angle, and failure mode of a layered rock mass under different fracture modes were analyzed by utilizing improved asymmetric semi-circular disc specimens. According to the constitutive model of transversely isotropic materials, the maximum tensile stress (MTS), maximum energy release rate (MERR), and maximum strain energy density (MSED) calculation formulas were modified, and the calculation formulas of the three prediction criteria under anisotropic materials were derived. The calculation results were compared with the experimental results. The results show that the fracture toughness and crack deflection angle were significantly affected by the weak bedding plane. As a result of applying the MTS criterion, the results are closer to the experimental results, providing a solid foundation for engineering deformation, failure, and fracture analyses. [ABSTRACT FROM AUTHOR]

A novel LED driver is proposed and analyzed in this paper. The main circuit topology is based on a quadratic buck and a buck-boost. They share a switch through cascading, simplifying the topology and control strategy, reducing the cost of the control circuit. Using two-stage cascade structure, the input current dead-time problem of the original quadratic buck topology is eliminate. It improves the power factor and the input current THD. At the same time, the duty cycle of the switch operates in a more reasonable area. Finally, the correctness of the theoretical analysis is verified by experiments.

Erythromycin fermentation process is a typical microbial fermentation process. Soft sensors can be used to estimate biomass of Erythromycin fermentation process for their relative low cost, simple development, and ability to predict difficult-to-measure variables. However, traditional soft sensors, e.g. artificial neural network (ANN) soft sensors, support vector machine (SVM) soft sensors, etc., cannot represent the uncertainty (measurement precision) of outputs. That results in difficulties in practice. Gaussian process regression (GPR) provides a novel framework to solve regression problems. The output uncertainty of a GPR model follows Gaussian distribution, expressed in terms of mean and variance. The mean represents the predicted output. The variance can be viewed as the measure of confidence in the predicted output that distinguishes the GPR from NN and SVM soft sensor models. We proposed a systematic approach based on GPR and principal component analysis (PCA) to establish a soft sensor to estimate biomass of Erythromycin fermentation process. Simulations on industrial data from an Erythromycin fermentation process show the proposed GPR soft sensor has high performance of modeling the uncertainty of estimates.

The theoretical model for group-forced infragravity (IG) waves in shallow water is not well established for nonbreaking conditions. In the present study, analytical solutions of the group-forced IG waves at O(β1) (β1 = hx/(Δkh), hx = bottom slope, Δk = group wavenumber, h = depth) in intermediate water and at O ⁡ (β 1 − 1 ) in shallow water are derived separately. In case of off-resonance [β1μ−1 = O(β1), where μ = 1 − c g 2 / (g h) is the resonant departure parameter, cg = group speed] in intermediate water, additional IG waves in quadrature with the wave group forcing (hereinafter, the nonequilibrium response or component) are induced at O(β1) relative to the equilibrium bound IG wave solution of Longuet–Higgins and Stewart (1962) in phase with the wave group. The present theory indicates that the nonequilibrium response is mainly attributed to the spatial variation of the equilibrium bound IG wave amplitude instead of group-forcing. In case of near-resonance [β1μ−1 = O(1)] in shallow water; however, both the equilibrium and nonequilibrium components are ~ O ⁡ (β 1 − 1 ) at the leading order. Based on the nearly-resonant solution, the shallow water limit of the local shoaling rate of bound IG waves over a plane sloping beach is derived to be ~h−1 for the first time. The theoretical predictions compare favorably with the laboratory experiment by Van Noorloos (2003) and the present numerical model results generated using SWASH. Based on the proposed solution, the group-forced IG waves over a symmetric shoal are investigated. In case of off-resonance, the solution predicts a roughly symmetric reversible spatial evolution of the IG wave amplitude, while in cases of near to full resonance the IG wave is significantly amplified over the shoal with asymmetric irreversible spatial evolution. [ABSTRACT FROM AUTHOR]

The present paper aims to clarify the mechanism of infragravity wave (IGW) energy amplification over nearshore shoals reported in recent studies. Wave transformation and energy transfer between short waves (SWs) and IGWs were investigated using SWASH model for nonbreaking random waves propagating over trapezoid shoals with different bottom slopes. It was found that the time lag of IGWs relative to SW groups is the major mechanism for energy transfer from SWs to IGWs and the amplification of IGW energy over all segments of the shoal. The time lag is generated on the front slope and enlarged on the plateau of the shoal, decreases on the rear slope with higher decreasing rates on milder slopes. Over the rear slope, the evolution of IGWs depends on the relative importance of deshoaling and nonlinear energy transfer. It was found that nonlinear energy transfer dominates over the rear slope gentler than 1/60, causing the IGW energy to increase over the first half of the deshoaling process and decrease over the second half whereas deshoaling dominates for steeper rear slope and the IGW energy decay over the whole slope. It is demonstrated numerically and theoretically that the shoals with gentler bottom slopes amplify the IGW energy more effectively by providing longer distance for nonlinear energy transfer to build up. The persistent nonlinear energy transfer on the plateau indicates the important role of wave spatial evolution history in the subsequent IGWs evolution. Strong free IGWs were detected on leeward of the shoal, possibly due to release of topography‐induced additional bound IGWs. Key Points: Wave spatial evolution history has significant effects on the subsequent evolution of infragravity wavesInfragravity wave energy is significantly amplified in the direction of wave propagation by a near shore shoalShort waves continually transfer energy to infragravity waves when propagating across the shoal even in the deshoaling zone [ABSTRACT FROM AUTHOR]

Aiming at the leakage current problem of single-phase transformerless photovoltaic(PV) grid-connected inverters, the recent proposed topologies are classified and reviewed. These topologies are divided into half-bridge type and full-bridge type. The topology characteristics of transformerless PV inverter are analyzed. This paper presents some of transformerless PV inverter topologies and discusses the evolution laws among various topologies to clarify the interrelationship between them. Furthermore, according to the evolution laws, a new topology is proposed. Finally, Simulations and experiments compare leakage current suppression capability of the proposed topology, H5 topology and HERIC topology. [ABSTRACT FROM AUTHOR]

NUT carcinoma (NC) is an aggressive squamous tumor characterized by NUT gene rearrangement, and the most common fusion form is BRD4-NUT. However, NC diagnosis is difficult for its rareness and often being confused with a variety of poorly differentiated tumors. A 21-year-old Chinese woman was referred to our hospital for cough and intermittent fever. Chest computed tomography (CT) imaging revealed a left lobe hilar mass. Fiberoptic bronchoscopy results showed that tumor cells were poorly differentiated. In combination with immunohistochemistry staining, she was misdiagnosed with Ewing's sarcoma/primitive neuroectodermal tumor. Next-generation sequencing (NGS) revealing BRD4-NUT fusion, and NUT immunohistochemistry confirmed the diagnosis of NC. Subsequently, left pneumonectomy and lymph node dissection were performed, and the patient received pemetrexed and lobaplatin treatment. NGS technology played an important role in NC diagnosis in this case, and it may have clinical use for rare cancer diagnosis and guidance of potential targeted therapies. [ABSTRACT FROM AUTHOR]

A new nonlinear compact LED model is presented in this paper. The model is useful in the design stage of LED driver system. The parameter extraction procedure is presented step by step. Since the power of a single LED unit is very low, manufacturers often arrange LED units in the form of an array named LED module. On the basis of theoretical I-V characteristic curve of the LED module, the electrical performance of LED module can be tested according to the rated parameters provided by its manufacturers. Five fitting methods are used to obtain the fitting curves. The sum of squares due to error (SSE) and the coefficient of determination (R-square) are compared to choose a better fitting curve. Six terms gaussian fitting method, which has optimal fitting performance among the five methods, is chosen to construct the nonlinear mathematical model of the LED module, and then the simulation model is built with MATLAB/Simulink. A Boost converter simulation circuit adapts this model, and a 25 W dimming prototype is designed to verify the validity of the model. The simulation and test results show that the error of the model is small, and it meets the requirements of practical application. [ABSTRACT FROM AUTHOR]

A 34-year-old man presented with facial asymmetry and was diagnosed with left-sided hemimandibular hyperplasia. Orthognathic surgery and mandibular angle osteotomy combined with inferior alveolar nerve repositioning were performed with computer-aided design. The facial asymmetry was successfully corrected with acceptable cosmetic results. Inferior alveolar nerve repositioning provided sufficient space for the osteotomy of the affected side with the abnormal mandibular canal. Inferior alveolar nerve repositioning with computer-aided design can be used as an effective and reliable technique for hemimandibular hyperplasia., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 by Mutaz B. Habal, MD.)

Objective: To investigate the frequency of USP6 gene rearrangement in nodular fasciitis (NF) and to evaluate its clinical application., Methods: Twenty nine cases of previously diagnosed NF were screened for the presence of the USP6 gene rearrangement by interphase fluorescence-in-situ hybridization (FISH) on formalin-fixed paraffin-embedded tissue. Fifteen of these cases, which had available tissue, were also analysed for MYH9-USP6 fusion transcripts by reverse transcription-polymerase chain reaction (RT-PCR)., Results: Twenty four of the 29 cases (83%) were positive for the USP6 gene rearrangement by interphase FISH. The 15 cases with RT-PCR showed the following results: 11 positive, one deletion and three negative for USP6 gene rearrangement. Of these 15 cases, eight (8/15) showed MYH9-USP6 fusion transcript by RT-PCR. Of these eight cases, seven were positive for USP6 gene rearrangement and one showed USP6 deletion by FISH., Conclusions: USP6 gene rearrangement is a recurrent genetic event in NF. It is a valuable ancillary tool for the pathological diagnosis of these lesions.

Peutz-Jeghers syndrome (PJS) is a rare inherited autosomal dominant disease characterized by mucocutaneous pigmentation and multiple polyps in the gastrointestinal tract. We report on an 18-year-old Chinese male who complained with pigmentation on face and extremities for over 10 years. Colonoscopy revealed more than ten polyps from transverse colon to rectum. The family survey included 15 family members from three generations, and 6 PJSs (4 males and 2 females) were found. This case is reported because of its rarity of Peutz-Jeghers syndrome and the survey of family history.

Objective: This study was to explore the expression and clinicopathologic features of Tyrosine kinase receptors B (TrkB) and its ligand brain-derived neurotrophic factor (BDNF) in nasopharyngeal carcinoma (NPC)., Method: Immunohistochemistry was adopted to detect the expression level of TrkB and BDNF in NPC patients., Result: Both TrkB and BDNF were expressed in NPC as well as in chronic inflammation. The active expression rate of TrkB in NPC was 82.5% (47/57) and BDNF was 52.6% (30/57), both of which were higher than those in chronic inflammation (P < 0.05). The degree of TrkB expression was more marked in T3 + T4, III + IV stage NPC than that in T1 +T2, I + II stage NPC (P < 0.05). TrkB abnormal expression rate of nasopharyngeal carcinoma with lymph node metastasis was higher than that of NPC without lymph node metastasis (P < 0.05). No statistical significance for degrees of TrkB expression in pathologic type grades was found (P > 0.05). There were no statistical significance for degrees of BDNF expression in T stage, clinical stage and lymph node metastasis in NPC (P > 0.05). The expression of TrkB was unrelated to the expression of BDNF (r = 0.049, P > 0.05)., Conclusion: The high expression rate of TrkB and BDNF maybe plays an important role in development of NPC. It is suggested that TrkB and its ligand BDNF may act as an important index for forecasting the development and metastasis of NPC.